ABS solenoid/isolation valve integration into single-ended solenoid body, using master cylinder actuation

ABSTRACT

An anti-lock braking system (ABS) solenoid isolation valve integration is provided. When ABS is entered, the ABS supply pump is turned on and the solenoid normally open port is closed to prevent fluid from entering the wheel brake area from either the master cylinder or pump. The normally closed valve is then energized (opened) which releases pressure from the wheel causing a pressure drop across the isolation valve. The above causes the isolation valve to move closing a ball seat valve which isolates the master cylinder (pedal) from the wheel (pump, solenoid, etc). The actual movement of the isolation valve is caused by the pressure generated by the master cylinder.

FIELD OF THE INVENTION

The field of the invention is that of vehicle anti-lock brake apparatusand method of utilization thereof. The disclosure of U.S. Pat. No.4,860,794 to Parrot et al is incorporated by reference herein. Anexcellent example of a vehicle anti-lock brake apparatus can be found inBaughman et al U.S. Pat. No. 4,768,843.

DISCLOSURE STATEMENT

The isolation valve is a device which provides the function of isolatingthe master cylinder from the wheel brake cylinder during an anti-lockbrake (ABS) stop. This prevents the driver from feeling any pedal"flutter" which occurs during ABS as a result of pressure changes causedby rapid cycling of a solenoid valve in the brake circuit. Pedalfeedback may be felt as either a rise or drop when the isolation valvemoves at the beginning and end of the cycle depending on how theequalizer valve is proportioned. However, there will be no feedback dueto solenoid cycling.

The isolation valve function is normally packaged as a separate devicein the master cylinder body or brake modulator body (machine body).

SUMMARY OF THE INVENTION

The present invention is different from traditional approaches in thatthe isolation valve is integrated in with the solenoid housing. Theisolation valve required to perform in this mechanization consists of aroughly cylindrical piece of material (metal, plastic, etc.) with holesand ball valves allowing for fluid passage, and two O-ring sealsallowing passage isolation. One O-ring interfaces with the solenoidhousing, while the other interfaces with the machine body (main ABSactuator housing).

When ABS is entered, the ABS supply pump is turned on and the solenoidnormally open port is closed to prevent fluid from entering the wheelbrake area from either the master cylinder or pump. The normally closedvalve is then energized (opened) which releases pressure from the wheelcausing a pressure drop across the isolation valve. The above causes theisolation valve to move closing a ball seat valve which isolates themaster cylinder (pedal) from the wheel (pump, solenoid, etc.). Theactual movement of the isolation valve is caused by the pressuregenerated by the pump in one version or the master cylinder in analternative version. Thus the term "pump pressure actuation" or "mastercylinder actuation" is utilized.

There are several benefits to the integrated isolation valve conceptincluding; reduced number of hardware pieces, elimination of the machinebody bores necessary to house the separate isolation valve assembly, andthe ability to provide the entire solenoid/isolation valve assembly as apackaged unit for vehicle assembly.

It is an object of the present invention to provide a solenoid/isolationvalve integration into a single ended solenoid body using mastercylinder pressure actuation for use in an anti-lock braking systemincluding a master cylinder, wheel cylinder, a reservoir, and a fluidpump, the valve including a housing for mounting the solenoid valve andthe isolation valve, the housing including fluid connection for themaster cylinder, wheel cylinder, reservoir and pump, the housing alsohaving a first fluid path connecting the master cylinder to the wheelcylinder with a ball seat, a second fluid path intersecting the firstfluid path connecting with the pump, a third fluid path intersectingwith the first fluid path and connecting with the reservoir, a fourthfluid path connecting the wheel with the master cylinder, a firstsolenoid having a first solenoid actuated plunger and valve member forcontrolling fluid communication in the first fluid path between theintersection of the first and second fluid paths and the wheel cylinderconnection, the first solenoid having a normally open position, a secondsolenoid having a second solenoid actuated plunger on the same side ofthe first and second solenoids as the first solenoid plunger, and thesecond solenoid plunger having a second valve member for controllingfluid communication in the third fluid path having a normally closedposition, a check valve mounted within the fourth fluid passage allowingflow from the wheel cylinder to the master cylinder, an isolation valveincluding a spool positionally biased within the second fluid path and aball contacted by the spool, the ball being nested in the seat in thefirst fluid path and whereby the isolation valve during normal brakeoperation allows fluid flow between the master cylinder and the wheelcylinder and when the pump is activated in an anti-lock braking systemmode the master cylinder pressure causes the isolation valve to slidewithin the first fluid path to push the ball against the valve seatisolating the master cylinder from the brake cylinder and allowing flowfrom the pump to the wheel cylinder in an anti-lock mode.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 and 1A represent a first embodiment of an anti-lock brakingsystem solenoid/isolation valve integration.

FIG. 2 represents a second embodiment of the invention.

Further objects, desires and advantages of the present invention canbecome more apparent to those skilled in the art as the nature of theinvention is better understood from the accompanying drawings and adetailed description.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGS. 1 and 1A the anti-lock braking systemsolenoid/isolation valve integration 7 has an ABS machine body oractuator housing 6. The housing 6 has mounted thereto a solenoid orinner housing 12 with first 61 and second 67 solenoid coils similar tothat shown and described in Parrot et al U.S. Pat. No. 4,860,794. Thefirst 61 and second 67 solenoids are surrounded by a casing 8. The firstsolenoid coil 61 activates a generally cylindrical stem 66 whichcontacts annular valve member 62 which in turn presses valve member orball 63. The second solenoid coil 67 activates a second valve stem 52which extends through the first valve member 62 and has integrallyjoined thereto a second valve member 53. The first 62 and second 52valve plungers are on a common side of the first and second solenoidcoils 61, 67.

The solenoid/isolation valve integration 7 is used in an anti-lockbraking system. The anti-lock braking system also includes a mastercylinder 32, a wheel cylinder 34 (Note: wheel cylinder as used in thisapplication refers to drum-type brake cylinders or calipers of a disctype brake), a brake fluid reservoir 37, and a pressurized fluid source38. Typically, the pressurized fluid source 38 will be a hydraulic pumpor an accumulator which is fed by a hydraulic pump.

The housing 6 mounts the solenoid valve casing 8 and the solenoidisolation valve 80. The housing 6 has fluid connections for thereservoir 40, the master cylinder 30, the wheel cylinder 20 and the pump10. The housing 6 has a bore 9 with the inner housing 12 mountedtherein. A first fluid path is provided by radial bore 11, bore 13, bore14, bore 15, bore 16, bore 17 and radial bore 18 to connect the mastercylinder connection 30 with the wheel cylinder connection 20. A valveseat 83 is provided between bores 13 and 14. A valve seat 64 for theball 63 associated with the first valve plunger 62 is located within anarrowed portion of bore 15. A spring 87 biases a ball 82 away from thevalve seat 83. Filters 24, 25, 27 and 28 are provided in an attempt tokeep the fluid within the solenoid/isolation valve integration 7 asclean as possible.

Intersecting the first fluid path is a second fluid path provided byradial bore 22, bore 21 and bore 14. The second path connects with thepump connection 10. The first fluid path is also intersected with athird fluid path provided by bore 16, bore 36 and radial bore 29. Thethird fluid path leads to the reservoir connection 40. The intersectionof the third fluid path with the first fluid path is after theintersection of the first and second fluid paths but prior to theconnection of the wheel 20. A forth fluid path 19 along the outercircumference of the inner housing 12 past V-seal 75 is provided betweenthe wheel cylinder 20 and the master cylinder 30 connections.

Fluid communication through the first fluid passage is controlled by thefirst solenoid valve and its associated valve member 62 and ball 63. Thesecond solenoid valve stem 52 and valve member 53 (shown in the normallyclosed position) controls fluid communication through the third fluidpath. Slidably and sealably mounted within the second fluid path bores14 and 21 is the isolation valve 80. The isolation valve 80 has a largersection 81 slidably and sealably mounted within a bore 21 of the housing6. The isolation valve 80 has a surface 89 for contact with the ball 82.The isolation valve 80 is positionally biased by a return spring 84,located within a multidiametered internal bore 85 of the isolation valve80 is a check valve 86. Check valve 86 allows fluid flow towards theintersection of the first and second path but does not allow fluid flowfrom the master cylinder to the pump. At the end of interior bore 85 ofthe isolation valve spool is an orifice 95 providing a pressurebuild-up. Axially aligned O-rings 96 and 97 seal the isolation valvewithin housing 6 and inner housing 12, respectively.

Under normal brake apply, fluid from the master cylinder enters thehousing through the master cylinder connection 30 and passes over theball 82 and up the bore 15, past the ball 63 and then down bore 17exiting a screen through the wheel cylinder connection 20. On release ofthe brakes the fluid will return through the wheel connection 20 toforth fluid path 19 compressing the V-seal 75. The fluid will thenreturn to the master cylinder via connection 30. If desired, a separatebore in the housing 6 along with an included check valve could replacethe return forth passage 19.

Flow from the master cylinder to the pump is prevented by the checkvalve 86.

When the vehicle goes into an impending skid, an electronic controlmodule (not shown) signals the solenoids 1 and 2 and fluid pump. Theabove causes the ball 63 to mate with seat 64. At the same time thefluid pump is turned on to provide fluid pressure for the ABS stop. Thesecond stem 52 is lifted removing valve member 53 from bore 36 therebyreleasing pressure from the wheel cylinder 32 back to the reservoir. Theabove-mentioned change in pressure at the wheel cylinder along with thealready high pressure at the pump causes the isolation valve 80 to moveinto the inner housing 12 until the ball 82 mates with seat 83. Ball 82closes the access from the master cylinder 32 to the bore 14 isolatingthe master cylinder 32 from the pump 38 and wheel 34. Thus the term,"PUMP Pressure Actuation" is associated with the solenoid/isolationvalve integration 7. The ABS cycles are executed using fluid pressuresupplied by the pump 38 allowing apply, release and hold cycles byrespective movement of solenoid plungers 62 and 52 until ABS is nolonger required, at which time the driver releases pressure from thebrake pedal causing a drop in master cylinder 32 pressure. The pump 38is also turned off at this time. When the above occurs, pressure in themaster cylinder 32 and wheel cylinder 34 are equalized via the V-sealand the isolation valve 80 is returned to its original position by thereturn spring 84. If desired, orifice 95 which is the primary ABSreapply orifice can be relocated upstream of the isolation valve in thepump circuit. Additionally, if desired, the master cylinder andreservoir connections can be reversed.

Referring to FIG. 2, there is provided a solenoid/valve integration 207with master cylinder 32 actuation. The operation of the solenoids andassociated first plunger 262, ball 263, second plunger 252, valve member253 is similar to that explained in regards to solenoid/isolation valveintegration previously explained and will therefore be deleted in theinterest of brevity. The housing 206 is similar to housing 106 havingconnections for the reservoir 240, pump 210, wheel 220 and mastercylinder 230.

An inner housing 212 is fitted within bore 209 of housing 206. A firstfluid path connecting the master cylinder 232 with the wheel cylinder234 is provided by bores 230, 221 (via 285), 214, 213, 215, 216, 217,209 and 218. The first fluid path connecting with pump connection 210and intersecting the first fluid path is provided by bore 211. A thirdfluid path connected with the reservoir connection 240 is provided bybores 236 and 229.

An isolation valve shaped like an invert "T" is slidably and sealablymounted with bores 214 and 221 with an longitudinal interior bore 285and a radial bore 249. O-ring 297 sealably separates wheel pressure fromthe master cylinder 32 pressure. Radial bore 259, radial bore 249, andbore 285 provide a forth fluid path. The forth fluid path has a checkvalve 275 which allows flow from the wheel cylinder 234 back to themaster cylinder 232 to release the brakes in normal operations. Inoperation the fluid from the master cylinder connection 230 enters intothe isolation valve bore 285 past a spring 287 biased ball 282,continuing through the first fluid path and through the normally openwheel cylinder connection 220. The base brake return is along the forthfluid path to the wheel cylinder connection 220, through the check 275,bores 259, 249 and 285, and back to the master cylinder connection 230.In the base brake mode the isolation valve is in the fully extendedposition opposite inner housing 212, held in place by a return spring284 captured between the inner housing 206 and the isolation valve 280.

When the vehicle goes into an impending skid, the electronic controlmodule signals the solenoid 1 and the fluid pump 238. The normally opensolenoid 1 coil is energized causing the ball valve 263 to be presseddownward shutting off flow. At the same time the fluid pump is turned onto provide fluid pressure for the ABS stop. The normally closed solenoid2 coil is then energized releasing pressure from the wheel cylinder 234back to the reservoir 237. The above change in pressure at the wheelcylinder 234 along with the already high pressure at the master cylinder232, causes the isolation valve 280 to move into the inner housing 212until the ball 282 mates on a first fluid path seat 283 on the isolationvalve. Thus the term "Master Cylinder Actuation" is utilized. The ABScycles are executed using fluid pressure supplied by the pump 238allowing apply, release and hold cycles until ABS is no longer required,at which time the driver releases pressure from the brake pedal causinga drop in master cylinder 232 pressure. At the same time the pump isturned off. When this occurs, pressure in the master cylinder 232 andwheel cylinder 234 are equalized via the check valve 275 and theisolation valve 280 is returned to its original position by the returnspring 284.

Response time of the solenoid isolation valve integration 207 isexcellent and is the best possible (with the exception of a system usinga pressure accumulator) because the pressure is already in place to movethe isolation valve 280 due to the master cylinder. Response time forfirst cycle release is very good because of this, but the first reapplycycle must wait until the pump comes to pressure.

While embodiments of the present invention have been explained, it willbe readily apparent to those skilled in the art of the variousmodifications which can be made to the present invention withoutdeparting from the spirit and scope of this application as it isencompassed by the following claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A solenoid/isolationvalve integration into a single ended body using master cylinderactuation for use in an anti-lock braking system including a mastercylinder, wheel cylinder, reservoir, and a pressurized fluid source,said valve integration in combination comprising:a housing for mountingsaid solenoid valve and said isolation valve, said housing includingfluid connections for said master cylinder, wheel cylinder, reservoirand said pressurized fluid source, said housing also having a firstfluid path connecting said master cylinder to said wheel cylinder, asecond fluid path intersecting said first fluid path and connecting withsaid pressurized fluid source and a third fluid path intersecting withsaid first fluid path and connecting with said reservoir; a firstsolenoid having a first solenoid actuated valve member for controllingfluid communication in said first fluid path between said intersectionof said first and second fluid paths and said wheel cylinder connection,said first solenoid having a normally open position; a second solenoidhaving a second solenoid actuated valve member positionally located onthe same side of said first and second solenoids as said first solenoidvalve member, and said second solenoid valve member controlling fluidcommunication in said third fluid path and said second solenoid having anormally closed position; and an isolation valve mounted within saidfirst fluid path with a portion sealably separating said master cylinderfrom said wheel cylinder and when said anti-lock braking system isactuated said normally open solenoid valve member is closed and saidnormally closed solenoid valve member is opened allowing fluid to flowfrom said wheel cylinder to said reservoir and said isolation valvemoves within said first fluid path by a pressure force provided by saidmaster cylinder to isolate said master cylinder from said wheelcylinder.
 2. A valve integration as described in claim 1 furthercomprising a fourth fluid path between said master cylinder and saidwheel cylinder with a check valve mounted therein allowing for fluidcommunication from said wheel cylinder to said master cylinder.
 3. Avalve integration as described in claim 1 wherein said isolation valvehas a ball member, and said isolation valve has a spool with an internalbore and with a lower part sealably mounted within said first fluid pathwith an upper part for contact with a ball member to seal off saidmaster cylinder from said wheel cylinder.
 4. A valve integration asdescribed in claim 2 wherein said isolation valve is a spool slidablymounted within said first passage and wherein said isolation valve has ainternal bore and a cross bore intersecting with said forth passageallowing fluid flow from said wheel cylinder back to said mastercylinder through said isolation valve.
 5. A solenoid/isolation valveintegration into a single ended body using master cylinder actuation foruse in an anti-lock braking system including a master cylinder, wheelcylinder, a reservoir, and a fluid pump, said valve integration incombination comprising:a housing for mounting said solenoid valve andsaid isolation valve, said housing including fluid connections for saidmaster cylinder, wheel cylinder, reservoir and pump, said housing alsohaving a first fluid path connecting said master cylinder to said wheelcylinder with a seat, a second fluid path intersecting said first fluidpath connecting with said pump, a third fluid path intersecting withsaid first fluid path and connecting with said reservoir, a fourth fluidpath connecting said wheel cylinder with said master cylinder; a firstsolenoid having a first solenoid actuated valve member for controllingfluid communication in said first fluid path between the intersection ofsaid first and second fluid paths and said wheel cylinder connection,said first solenoid having a normally open position; a second solenoidhaving a second solenoid actuated valve member on the same side of saidfirst and second solenoids as said first solenoid valve member, and saidsecond solenoid valve member controlling fluid communication in saidthird fluid path, and said second solenoid having a normally closedposition; a check valve mounted within said fourth fluid path allowingflow from said wheel cylinder to said master cylinder; an isolationvalve including a spool positionally biased within said first fluid pathand a ball for contact by said spool, said spool having an internal boretherethrough and said spool having a portion sealably separating saidmaster cylinder from wheel cylinder and said spool having a radial boreforming a portion of said forth fluid passage whereby when saidanti-lock braking system is actuated and said normally open solenoidvalve is closed and said normally closed solenoid valve is open allowingfluid to flow from said wheel cylinder to said reservoir said isolationvalve moves within said first fluid path to contact said ball with saidseat by a pressure force provided by said master cylinder to isolatesaid master cylinder from said wheel cylinder.
 6. A method of using amaster cylinder to activate an isolation valve of an anti-lock brakingsystem solenoid/isolation valve integration utilizing a single endedsolenoid body wherein said anti-lock braking system includes a mastercylinder, wheel cylinder, reservoir, and a pump, said method incombination comprising:housing said solenoid valve and said isolationvalve in a common housing which includes fluid connections for a mastercylinder, wheel cylinder, reservoir, pressurized fluid source and afirst fluid path connecting said master cylinder to said wheel cylinder,a second fluid path intersecting said first fluid path and connectingwith said pressurized fluid source and a third fluid path intersectingwith said first fluid path and connecting with said reservoir;controlling fluid communication within said first fluid path by a firstsolenoid actuated valve member in said first fluid path between theintersection of the said first and second fluid paths and said wheelcylinder and biasing said first solenoid valve member to an openposition; controlling fluid communication in said third fluid path witha second solenoid actuated normally closed valve member being positionedon the same side of said first and second solenoids as said firstsolenoid valve member; and mounting within said intersection of saidfirst and second fluid paths means allowing fluid flow between the saidmaster cylinder and said wheel cylinder in normal braking operation andisolating said first fluid path from said fluid cylinder by the pressurein said master cylinder when said wheel cylinder is fluidly connectedwith said third fluid path when said braking system is in an anti-lockbraking mode.